Changes in the age of onset of multiple sclerosis.

This is a population-based cohort study of persons diagnosed with RRMS in Hordaland, Møre, and Romsdal counties, Western Norway, from 1920 to 2022. Individual patient data were available and assessed from previously conducted prevalence and incidence studies in addition to hospital records up until October 31, 2022. Participants were categorized according to onset period and analyzed for temporal trends in age at onset, time from onset to diagnosis, and distribution of onset over time.

Age at onset of MS significantly increased throughout the study period. This was mainly due to an increasing number of persons with MS, predominantly female, experiencing onset after 40–45 years of age. This bimodal distribution could indicate different susceptibility periods of MS or changes in exposure to risk factors during the observation period.

Source: Journal of Neurology